Shape memory alloy active hatch vent

ABSTRACT

A vent assembly is disposed within an interior space of a vehicle for opening and closing fluid communication between the interior space and an exterior of the vehicle. The vent assembly includes a housing defining a plurality of openings and a plurality of vanes disposed in the openings. An actuator mechanism moves the vanes between an open position and a closed position, and includes a shaped memory alloy (SMA) member for actuating the vanes between the open and closed positions. The SMA member is activated when a hatch of the vehicle is opened to move the vanes into the open position and thereby open fluid communication between the interior space and the exterior to alleviate excessive air pressure buildup during closure of the hatch.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a divisional patent application of U.S. patentapplication Ser. No. 12/612,112, filed on Nov. 4, 2009, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 61/220,806,filed Jun. 26, 2009, the disclosures of which are hereby incorporated byreference.

TECHNICAL FIELD

The disclosure generally relates to a vent assembly for an interiorspace of a vehicle, and more specifically to a method of operating avent assembly for alleviating excessive air pressure buildup in responseto closing a hatch of the vehicle.

BACKGROUND

Automotive vehicles include a body defining an interior space, forexample a cabin space or a trunk space. The interior space is closed bya hatch, such as a door or a trunk lid. The hatch and/or the bodyinclude seals to tightly seal the closure against the body to preventdebris, water, noise, etc, from entering the interior space of thevehicle from around a periphery of the closure. These seals also preventair from escaping as the hatch is closed, thereby causing an increase inair pressure within the interior space of the vehicle. The increased airpressure within the interior space resists the closing of the hatch,thereby increasing the effort required to close the hatch.

In order to alleviate the buildup of air pressure within the interiorspace of the vehicle when closing the hatch, some vehicles are equippedwith passive pressure relief valves. The passive pressure relief valvesopen in response to increased air pressure within the interior space ofthe vehicle to allow air within the interior space to escape, therebyreducing the air pressure within the interior space of the vehicle andreducing the effort to close the hatch. The passive pressure reliefvalves may include a flexible flap, such as a rubber flap, that ispushed open by the increased air pressure created during closure of thehatch. These types of passive pressure relief valves are biased to closeonce the air pressure within the interior space of the vehicle equalizeswith the ambient air pressure outside of the vehicle.

SUMMARY

A vent assembly for selectively opening and closing an interior space ofa vehicle to permit air within the interior space of the vehicle to exitthe interior space of the vehicle is disclosed. The vent assemblyincludes a housing that defines a plurality of openings. The ventassembly further includes a plurality of vanes, with one of theplurality of vanes disposed within each of the plurality of openings.Each of the plurality of vanes is pivotably attached to the housing andis configured for movement in unison between an open position and aclosed position. The open position permits fluid flow through theplurality of openings. The closed position prevents fluid flow throughthe plurality of openings. The vent assembly further includes anactuator mechanism attached to the housing and coupled to at least oneof the plurality of vanes. The actuator mechanism is configured formoving the plurality of vanes between the open position and the closedposition. The actuator mechanism includes a transmission coupled to thevanes and configured for transmitting rotation to the vanes, and a shapememory alloy member coupled to the transmission. The shape memory alloymember is configured for actuating the transmission in response to anelectrical signal.

A method of operating a hatch on a vehicle is also disclosed. Thevehicle defines an interior space and includes a vent assembly that ismoveable between an open position and a closed position. The openposition permits fluid flow into and out of the interior space of thevehicle. The closed position prevents fluid flow into and out of theinterior space of the vehicle. The method includes opening the hatch;automatically signaling the vent assembly to move into the open positionin response to the opening of the hatch; closing the hatch; andautomatically signaling the vent assembly to move into the closedposition in response to the closing of the hatch.

Accordingly, the vent assembly provides an active vent assembly thatpro-actively opens fluid communication between the interior space of thevehicle and an exterior of the vehicle to alleviate the air pressurewithin the interior space during closing of the hatch. Pro-activelymoving the vent assembly into the open position as soon as the hatch isopened eliminates the need to build up air pressure within the interiorspace during closure of the hatch prior to opening fluid communicationto alleviate excessive air pressure, thereby reducing the effortrequired to close the hatch.

The above features and advantages and other features and advantages ofthe present disclosure are readily apparent from the following detaileddescription of the best modes for carrying out the disclosure when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a vent assembly.

FIG. 2 is a perspective view of the vent assembly in a closed position.

FIG. 3 is a perspective view of the vent assembly in an open position.

FIG. 4 is a partial fragmentary perspective view of an actuatormechanism of the vent assembly in the closed position.

FIG. 5 is a partial fragmentary perspective view of the actuatormechanism of the vent assembly in the open position.

FIG. 6 is a partial fragmentary perspective view of the actuatormechanism.

FIG. 7 is a side plan view of the vent assembly installed in a vehicle.

DETAILED DESCRIPTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, a vent assembly is shown generallyat 20. The vent assembly 20 is for a vehicle, and opens and closes fluidcommunication between an interior space 21 of the vehicle and anexterior of the vehicle. Open fluid communication between the interiorspace 21 and the exterior of the vehicle alleviates excessive airpressure from within the interior space 21 in response to closing ahatch 23 of the vehicle.

Referring to FIG. 1, the vent assembly 20 includes a housing 22, aplurality of vanes 24 pivotably attached to the housing 22, and anactuator mechanism 26 attached to the housing 22 and configured formoving the plurality of vanes 24 in unison between an open position anda closed position. The closed position, shown in FIG. 2, prevents fluidcommunication between the interior space 21 of the vehicle and theexterior of the vehicle. The open position, shown in FIG. 3, permitsfluid communication between the interior space 21 of the vehicle and theexterior of the vehicle. While the vent assembly 20 shown and describedin the Figures includes five vanes 24, only two of the five vanes 24 areshown in FIGS. 2 and 3 for clarity.

The housing 22 defines a plurality of openings 28. As shown, the housing22 defines five different openings 28. However, it should be appreciatedthat the housing 22 may include any number of openings 28, and that theplurality of vanes 24 will include an equivalent number of vanes 24. Itshould also be appreciated that the openings 28 and the vanes 24 may besized and/or configured other than shown to meet specific designrequirements and packaging constraints.

One of the vanes 24 is disposed adjacent each of the openings 28. Thevanes 24 are moveable between the open position and the closed positionto open and close fluid communication through the openings 28. The ventassembly 20 includes a seal on at least one of the housing 22 and/or thevanes 24 to tightly seal the vanes 24 against the housing 22 when thevanes 24 are in the closed position. The seal may include and bemanufactured from any suitable material capable of sealing between thevanes 24 and the housing 22 to prevent dirt, dust, water and noise fromentering into the interior space 21 of the vehicle when the vanes 24 arein the closed position. It should also be appreciated that the seal maybe configured in any suitable shape and configuration to meet the designrequirements and constraints of the vehicle.

Each of the vanes 24 includes a first edge 30 adjacent a pivot axis 32about which the vane 24 pivots relative to the housing 22. The vanes 24are coupled to the housing 22 along the pivot axis 32, adjacent thefirst edge 30 of the vanes 24. The vanes 24 may be pivotably coupled tothe housing 22 in any suitable manner. It is contemplated that the vanes24 may include a boss extending outward along the pivot axis 32, withthe boss being received within a recess defined by the housing 22 tocreate the pivotable connection between the vanes 24 and the housing 22.It is alternatively contemplated that the vent assembly 20 may include apin 34 extending through the housing 22 into a bore 36 defined by thevanes 24 and rotatably supported by a bushing 38 to create the pivotableconnection between the vanes 24 and the housing 22. It should beappreciated that the pivotable connection between the vanes 24 and thehousing 22 may be accomplished in some other manner not shown ordescribed herein, and may include a combination of different styles ofpivotal connections.

Each of the vanes 24 includes a second edge 40 generally parallel to andspaced from the first edge 30. A linkage 42 couples each of the vanes 24together adjacent the second edge 40 to move the vanes 24 in unison.Accordingly, as will be described in greater detail below, the actuatormechanism 26 is coupled to at least one of the vanes 24, hereinafterreferred to as a drive vane 44, to move the drive vane 44 between theopen position and the closed position. The linkage 42 couples the drivevane 44 to the other remaining vanes 24 to move the remaining vanes 24in unison with the drive vane 44 between the open position and theclosed position. The vent assembly 20 includes a plurality of rivets 46interconnecting the linkage 42 and the vanes 24. It should beappreciated that the vanes 24 are pivotable relative to the linkage 42during movement between the open position and the closed position. Itshould also be appreciated that the linkage 42 may be pivotably attachedto the vanes 24 in some other manner not shown or described herein.

The housing 22 and the vanes 24 may include and be manufactured from anysuitable material, such as a plastic material, a composite material, ametal material, or some other similar rigid material capable ofmaintaining their form during operation to ensure a tight seal betweenthe vanes 24 and the housing 22.

The housing 22 may be assembled to the vanes 24 as described below. Thehousing 22 includes a first half and a second half. The first half andthe second half of the housing 22 are configured for a snap fitconnection therebetween. The linkage 42 is first assembled to the vanes24. The vanes 24 are then positioned in place relative one of the firsthalf and the second half. The first half and the second half of thehousing 22 are then snapped together, sandwiching the vanes 24therebetween. It should be appreciated that the housing 22 may beassembled to the vanes 24 in some other manner not shown or describedherein.

Referring back to FIG. 1, the actuator mechanism 26 includes a casing52. The casing 52 may be attached to the housing 22 through a pluralityof actuator fasteners 54, through a snap fit connection, or mayalternatively be integrally formed with the housing 22. The casing 52houses and supports a transmission 55. The transmission 55 is configuredfor rotating the vanes 24. The transmission 55 includes a vane gear 56and a geared lever 60. The casing pivotably supports the vane gear 56. Adrive shaft 58 couples the vane gear 56 to the drive vane 44 to move thedrive vane 44 between the open position and the closed position. Thevane gear 56 and the drive vane 44 are keyed for rotational movementwith the drive shaft 58. As such, the drive shaft 58 may include a Dshaded cross section or the like, with the vane gear 56 and the drivevane 44 defining a correspondingly shaped recess for receiving the driveshaft 58 therein in interlocking rotational engagement.

The casing pivotably supports the geared lever 60. The vane gear 56 andthe geared lever 60 are disposed in meshing engagement with each other.Referring to FIG. 4, the vane gear 56 and the geared lever 60 are shownin the closed position. Referring to FIG. 5, the vane gear 56 and thegeared lever 60 are shown in the open position. Upon actuation by theactuator mechanism 26, the geared lever 60 rotates clockwise asindicated by arrow 62. In response to the geared lever 60 rotatingclockwise, the vane gear 56 rotates counterclockwise, as indicated byarrow 64. The keyed connection between the vane gear 56, the drive shaft58, and the drive vane 44 causes the drive vane 44 to rotate relative tothe housing 22 from the closed position into the open position. A spring66 is coupled to the geared lever 60 and is configured to urge thegeared lever 60 back into the closed position. Accordingly, as will bedescribed in greater detail below, the spring 66 moves the geared lever60 from the open position, shown in FIG. 5, into the closed positionshown in FIG. 4. It should be appreciated that the transmission 55 maybe configured in some other manner capable of transferring the linearmovement of the SMA member 68 into rotational movement of the driveshaft 58. It should also be appreciated that the spring 66 may becoupled to other components of the vent assembly, such as one of thevanes 24, to urge the vanes into the closed position.

Referring to FIGS. 1, 4 and 5, the actuator mechanism 26 includes aShape Memory Alloy (SMA) member 68. The SMA member 68 is coupled to thetransmission 55, and is configured for actuating the transmission 55 inresponse to an electrical signal. The SMA member 68 includes a first endcoupled to the geared lever 60 and a second end coupled to the casing52. The SMA member 68 may be coupled to the geared lever 60 and thecasing 52 in any suitable manner, including the use of quick connectconnectors. The SMA member 68 is routed through a channel 70 defined bythe casing 52 to ensure that the SMA member 68 is separated from anyheat producing components of the actuator mechanism 26. Alternatively,the casing 52 may define a wall 96 to separate the SMA member 68 fromany heat producing components of the actuator mechanism 26. Separatingthe SMA member 68 from the electrical components ensures that the SMAmember 68 from shorting to any of the electrical components within theactuator mechanism 26.

In response to an electrical current, the SMA member 68 heats up andcontracts. Contraction of the SMA member 68 causes the geared lever 60to rotate from the closed position, shown in FIG. 4, into the openposition, shown in FIG. 5. In the absence of the electrical current, theSMA member 68 cools and returns to an original shape, i.e., length, ofthe SMA member 68. As described above, the spring 66 urges the gearedlever 60 into the closed position as the SMA member 68 expands duringcooling of the SMA member 68. As shown, the actuator mechanism 26 movesthe vanes 24 between the open position and the closed position. However,it should be appreciated that the actuator mechanism 26 may move thevanes 24 to any intermediate position between the open position and theclosed position, and hold the intermediate position as a final position.

The SMA member 68 includes and is manufactured from a shape memoryalloy. Suitable shape memory alloys can exhibit a one-way shape memoryeffect, an intrinsic two-way effect, or an extrinsic two-way shapememory effect depending on the alloy composition and processing history.The two phases that occur in shape memory alloys are often referred toas martensite and austenite phases. The martensite phase is a relativelysoft and easily deformable phase of the shape memory alloys, whichgenerally exists at lower temperatures. The austenite phase, thestronger phase of shape memory alloys, occurs at higher temperatures.Shape memory materials formed from shape memory alloy compositions thatexhibit one-way shape memory effects do not automatically reform, anddepending on the shape memory material design, will likely require anexternal mechanical force to reform the shape orientation that waspreviously exhibited. Shape memory materials that exhibit an intrinsicshape memory effect are fabricated from a shape memory alloy compositionthat will automatically reform themselves.

The temperature at which the shape memory alloy remembers its hightemperature form when heated can be adjusted by slight changes in thecomposition of the alloy and through heat treatment. In nickel-titaniumshape memory alloys, for example, it can be changed from above about100° C. to below about −100° C. The shape recovery process occurs over arange of just a few degrees and the start or finish of thetransformation can be controlled to within a degree or two depending onthe desired application and alloy composition. The mechanical propertiesof the shape memory alloy vary greatly over the temperature rangespanning their transformation, typically providing the shape memorymaterial with shape memory effects as well as high damping capacity. Theinherent high damping capacity of the shape memory alloys can be used tofurther increase the energy absorbing properties.

Suitable shape memory alloy materials include without limitationnickel-titanium based alloys, indium-titanium based alloys,nickel-aluminum based alloys, nickel-gallium based alloys, copper basedalloys (e.g., copper-zinc alloys, copper-aluminum alloys, copper-gold,and copper-tin alloys), gold-cadmium based alloys, silver-cadmium basedalloys, indium-cadmium based alloys, manganese-copper based alloys,iron-platinum based alloys, iron-platinum based alloys, iron-palladiumbased alloys, and the like. The alloys can be binary, ternary, or anyhigher order so long as the alloy composition exhibits a shape memoryeffect, e.g., change in shape orientation, damping capacity, and thelike.

The actuator mechanism 26 further includes a Printed Circuit BoardAssembly (PCBA 72). A stationary lead wire 74 is attached to the secondend of the SMA member 68 and the PCBA 72. A moveable lead wire 76 isattached to the first end of the SMA member 68 and the PCBA 72. Thestationary lead wire 74 and the moveable lead wire 76 conduct anelectrical current between the PCBA 72 and the SMA member 68 to actuatethe SMA member 68.

Referring also to FIG. 6, the PCBA 72 includes a printed circuit board78 and a power transistor 80 mounted to the printed circuit board 78.The power transistor 80 switches on the SMA member 68 by sending theelectrical current to the SMA member 68, and switches off the SMA member68 by disrupting the electrical current to the SMA member 68.

The PCBA 72 further includes a microcontroller 82 mounted to the printedcircuit board 78. The power transistor 80 is in communication with themicrocontroller 82. When the actuator mechanism 26 is powered, themicrocontroller 82 provides a pulse width modulated signal controllingthe power transistor 80 and the power supplied to the SMA member 68. Themicrocontroller 82 includes a program that provides anywhere from twopositions (on and off) to infinite position control. The program canadjust the pulse width modulated signal for many factors, such asambient temperature.

The PCBA 72 further includes a power connector 84 mounted to the printedcircuit board 78. The power connector 84 is in communication with themicrocontroller 82. The power connector 84 is an integrated printedcircuit board 78 connector that allows for easy attachment to the SMAmember 68.

The PCBA 72 further includes a thermistor 86 mounted to the printedcircuit board 78. The thermistor 86 is in communication with themicrocontroller 82. The thermistor 86 measures environmentaltemperatures for the microcontroller 82. The thermistor 86 is located onthe printed circuit board 78 away from any components that may generateheat.

The PCBA 72 further includes a harness connector 88 mounted to theprinted circuit board 78. The harness connector 88 is in communicationwith the microcontroller 82. The harness connector 88 connects the ventassembly 20 to the vehicle for receiving a signal, i.e., power from thevehicle, to actuate the vent assembly 20.

Referring back to FIG. 1, the actuator mechanism 26 further includes apotentiometer 90. The potentiometer 90 is in communication with themicrocontroller 82 and provides information related to the position ofthe drive shaft 58, and thereby information related to the position ofthe vane gear 56 and the drive vane 44, to the microcontroller 82. Thepotentiometer 90 is integrated into the printed circuit board 78, and iscoupled to the drive shaft 58. More specifically, the drive shaft 58extends through a keyed port defined by the potentiometer 90 to measurerotation of the drive shaft 58. Because the potentiometer 90 is coupledto the printed circuit board 78 and the drive shaft 58, precise locationof the PCBA 72 within the casing 52 is imperative to ensure the driveshaft 58 does not bind during operation. As such, the PCBA 72 isattached to the casing 52 via fasteners, a snap fit connection, or insome other manner capable of ensuring and maintaining the properposition of the potentiometer 90 relative to the drive shaft 58.

The actuator mechanism may include an electronic overload protectionsystem to prevent the SMA member 68 from being exposed to excessivestress. The microcontroller 82 is operable to control the electronicoverload protection system. The electronic overload protection systemmay include the potentiometer 90, the thermistor 86, and an algorithmoperable on the microcontroller 82. The electronic overload protectionsystem is operable to cut power to the SMA member 68 in the event thevanes 24 are restrained from movement. Specifically, the microcontroller82 may cut power to the SMA member 68 in the event the potentiometer 90senses the vanes 24 are restrained from movement. It should beappreciated that the electronic overload protection system may beconfigured other than described herein, in a manner capable ofprotecting the SMA member 68 from damage.

The actuator mechanism 26 further includes a cover 92. The cover 92 isattached to the casing 52, and seals the various components of theactuator mechanism 26 between the casing 52 and the cover 92. The cover92 may include a snap fit to the casing 52. Alternatively, the cover 92may be attached to the casing 52 through a plurality of fasteners.

Referring to FIG. 7, the vent assembly 20 may further include grille 94.The grille 94 is an interior trim piece of the vehicle, and preventsforeign objects from entering the vent assembly 20 and becoming lodgedbetween the vanes 24 and the housing 22. Preferably, a snap fitconnection attaches the grille 94 to the housing 22. However, it shouldbe appreciated that the grille 94 may be attached to the housing 22 insome other manner. As shown in FIG. 7, the vent assembly 20 is attachedto the vehicle. The housing 22 includes one or more clips integrallyformed with the housing 22. The clips attach the housing 22 to a wall 96of the vehicle. The housing 22 includes a gasket around an outerperiphery of the housing 22 to seal against the wall 96 of the vehicle,and prevent dust, dirt, water, air or noise from entering the interiorspace 21 of the vehicle around the outer periphery of the vent assembly20. The gasket may include any suitable type and configuration ofgasket. The grille 94 sandwiches an interior carpet 98 between thehousing 22 and the grill from within the interior space 21 of thevehicle to complete the installation.

In operation, the vent assembly 20 is attached to the vehicle, withinthe interior space 21 of the vehicle as described above. For example,the interior space 21 of the vehicle may be defined as a trunk and thehatch 23 may be defined as a trunk lid. The normal position of the ventassembly 20 is the closed position, wherein all of the vanes 24 aresealed against the housing 22 to prevent fluid communication between theinterior space 21 and the exterior of the vehicle. As described above,the spring 66 within the actuator mechanism 26 biases the geared lever60 into the closed position. The sealing force supplied by the spring66, in combination with the rigid vanes 24 and the seals between thevanes 24 and the housing 22 eliminate an influx of air, water, dirt,dust, or noise into the hatch 23.

The vent assembly 20 is actively opened on demand, i.e., the ventassembly 20 is opened automatically prior to closing the hatch 23.Preferably, the position of the hatch 23 triggers operation of the ventassembly 20. The vehicle includes a vehicle controller and a sensorsystem for sensing a position of the hatch 23, e.g., an open position ora closed position. The vehicle controller controls the operation of thevent assembly 20. The vehicle controller may include a computer and/orprocessor, and include all software, hardware, memory, algorithms,connections, sensors, etc., necessary to manage and control theoperation of the vent assembly 20. As such, a method, described below,may be embodied as a program operable on the vehicle controller. Itshould be appreciated that the vehicle controller may include any devicecapable of analyzing data from various sensors, comparing data, makingthe necessary decisions required to control the operation of the ventassembly 20 and executing the required tasks necessary to control theoperation of the vent assembly 20.

Once the sensor system indicates that the hatch 23 is open, the vehiclecontroller engages other vehicle systems, such as interior lights, etc.The vehicle controller and sensor system are also utilized to controlthe vent assembly 20. Accordingly, once the sensor system senses thatthe hatch 23 is open, the vehicle controller signals the vent assembly20 to move into the open position. The signal to the vent assembly 20 isthe device power supply, i.e., the vehicle controller signals the ventassembly 20 to move into the open position by supplying power to thevent assembly 20. The microcontroller 82 in the actuator mechanism 26directs the electrical current to the SMA member 68, which causes theSMA member 68 to heat. As the temperature of the SMA member 68increases, the SMA member 68 contracts, rotating the geared lever 60,and thereby the vanes 24, into the open position.

The vanes 24 of the vent assembly 20 remain in the open position untilthe sensor system senses that the hatch 23 is closed. As such, fluidcommunication from within the interior space 21 to the exterior of thevehicle is actively opened, i.e., automatically opened, whenever thehatch 23 is opened. The fluid communication remains open until the hatch23 is closed. Therefore, there is no air pressure buildup within theinterior space 21 as the hatch 23 closes because the air is free to exitthe interior space 21 through the vent assembly 20 as the hatch 23 isclosed. The prevention of air pressure buildup prior to closing thehatch 23 greatly reduces the closing effort required to close the hatch23. Once the sensor system senses that the hatch 23 is closed, thevehicle controller disconnects the power supply to the actuatormechanism 26, thereby disrupting the electrical current to the SMAmember 68. Without the electrical current, the SMA member 68 begins tocool and returns to the original length of the SMA member 68. The spring66 automatically urges the geared lever 60, and thereby the vanes 24,back into the closed position. Alternatively, in the event the hatch 23remains open, the actuator mechanism 26 may be configured to move thevanes 24 into the closed position after the expiration of apre-determined time interval.

The vent assembly 20 may include an alert feature configured to notifyan operator that the vent assembly 20 is disposed in the open position.The alert feature may include backlighting of the vanes, a warning lightin the vehicle, a buzzer, or some other system of notifying the operatorthat the vent assembly 20 is in the open position.

During operation of the vent assembly 20, the vehicle controller maysense if movement of the plurality of vanes 24, between the openposition and the closed position, is partially blocked by a blockage.The blockage may include, but is not limited to, an accumulation of snowand ice, or some mechanical malfunction or obstruction that is partiallyblocking the movement of the vanes 24. The vehicle controller may sensethe blockage in any suitable manner, such as by measuring a resistanceto movement of the vanes 24, or by comparing an actual position of thevanes 24 to a projected or modeled position of the vanes 24 for thecurrent given operating conditions of the vent assembly 20. It should beappreciated that the vehicle controller may sense and/or determine thatthe vanes 24 are obstructed by the blockage in some other manner notspecifically described herein.

When the vehicle controller senses that the plurality of vanes 24 areblocked from fully moving into the open position by the blockage, thevehicle controller may move the plurality of vanes into a partially openposition. The partially open position is a position disposed between theclosed position and the open position. More specifically, the vehiclecontroller may move the plurality of vanes 24 toward the open positionuntil the plurality of vanes 24 encounter the blockage preventingfurther movement of the plurality of vanes into the open position. Theposition at which the vanes encounter the blockage may be defined as thepartially open position. By only moving the vanes 24 into the partiallyopen position when the blockage prevents the vanes 24 from fully movinginto the open position, the vehicle controller limits potential damageto the vent assembly 20.

In order to prevent undesirable actuation, i.e., opening, of the ventassembly 20, the vehicle controller may monitor at least one operatingcondition of the vehicle. The at least one operating condition of thevehicle may include, but is not limited to, a speed of the vehicle or anambient air temperature of the vehicle adjacent the hatch 23. Thevehicle controller may then determine if all of the operating conditionsof the vehicle being monitored are within a respective allowable range,or are not within their respective allowable range. The allowable rangefor each of the different operating conditions of the vehicle is therange at which it is permissible to open the vent assembly 20, i.e., itis permissible to move the vanes 24 of the vent assembly 20 into theopen position. As such, if any of the operating conditions of thevehicle are outside of their respective allowable range, it is generallynot permissible to move the vent assembly 20 into the open position.

When all of the operating conditions of the vehicle being monitored bythe vehicle controller are within their respective allowable ranges, thevehicle controller may automatically signal the vent assembly 20 to moveinto the open position in response to the opening of the hatch 23.However, if any one of the plurality of operating conditions of thevehicle being monitored by the vehicle controller are not within theirrespective allowable ranges, then the vehicle controller may not signalthe vent assembly 20 to move into the open position in response to theopening of the hatch 23, thereby keeping the vent assembly 20 in theclosed position, even if the hatch 23 is opened.

While the best modes for carrying out the disclosure have been describedin detail, those familiar with the art to which this disclosure relateswill recognize various alternative designs and embodiments forpracticing the disclosure within the scope of the appended claims.

The invention claimed is:
 1. A method of operating a hatch on a vehicledefining an interior space and including a vent assembly moveablebetween an open position and a closed position, with the open positionpermitting fluid flow into and out of the interior space of the vehicleand the closed position preventing fluid flow into and out of theinterior space of the vehicle, the method comprising: opening the hatch;automatically signaling the vent assembly with a vehicle controller tomove into the open position in response to the opening of the hatch;wherein the vent assembly includes a plurality of vanes moveable betweenthe open position and the closed position, and a shape memory alloymember having a first end coupled to a geared lever and a second endcoupled to a casing, with the geared lever in meshing engagement with avane gear such that linear movement of the shape memory alloy memberrotates the geared lever and the vane gear, which in turn moves theplurality of vanes between the open position and the closed position,and wherein signaling the vent assembly to move into the open positionincludes heating the shape memory alloy member to contract the shapememory alloy member, thereby rotating the geared lever and the vane gearin a first direction to move the plurality of vanes into the openposition; closing the hatch; and automatically signaling the ventassembly with the vehicle controller to move into the closed position inresponse to the closing of the hatch; wherein the vent assembly includesa spring operable to urge the plurality of vanes into the closedposition, and wherein signaling the vent assembly to move into theclosed position includes cooling the shape memory alloy member toelongate the shape memory alloy member, thereby allowing the spring torotate the geared lever and the vane gear in a second direction to movethe plurality of vanes into the closed position.
 2. The method set forthin claim 1 further comprising sensing a position of the plurality ofvanes.
 3. The method set forth in claim 2 further comprising sensing ifmovement of the plurality of vanes between the open position and theclosed position is partially blocked by a blockage.
 4. The method setforth in claim 3 further comprising moving the plurality of vanes into apartially open position, disposed between the closed position and theopen position, when the plurality of vanes are blocked from fully movinginto the open position by the blockage.
 5. The method set forth in claim4 wherein moving the plurality of vanes into the partially open positionis further defined as moving the plurality of vanes toward the openposition until the plurality of vanes encounter the blockage preventingfurther movement of the plurality of vanes into the open position. 6.The method set forth in claim 1 further comprising monitoring at leastone operating condition of the vehicle.
 7. The method set forth in claim6 wherein the at least one operating condition of the vehicle is a speedof the vehicle or an ambient air temperature of the vehicle adjacent thehatch.
 8. The method set forth in claim 6 further comprising determiningif all of the at least one operating conditions of the vehicle arewithin a respective allowable range or are not within their respectiveallowable range.
 9. The method set forth in claim 8 whereinautomatically signaling the vent assembly with the vehicle controller tomove into the open position in response to the opening of the hatch isfurther defined as automatically signaling the vent assembly with thevehicle controller to move into the open position in response to theopening of the hatch, when all of the at least one operating conditionsof the vehicle are within their respective allowable range.
 10. Themethod set forth in claim 1 further comprising signaling the ventassembly to move into the closed position in response to the hatch beingpositioned in the open position for a pre-determined period of time. 11.A method of operating a hatch on a vehicle defining an interior spaceand including a vent assembly moveable between an open position and aclosed position, with the open position permitting fluid flow into andout of the interior space of the vehicle and the closed positionpreventing fluid flow into and out of the interior space of the vehicle,the method comprising: monitoring at least one operating condition ofthe vehicle; determining if all of the at least one operating conditionsof the vehicle are within a respective allowable range or are not withintheir respective allowable range; opening the hatch; automaticallysignaling the vent assembly with a vehicle controller to move into theopen position in response to the opening of the hatch, when all of theat least one operating conditions of the vehicle are within theirrespective allowable range; wherein the vent assembly includes aplurality of vanes moveable between the open position and the closedposition, and a shape memory alloy member having a first end coupled toa geared lever and a second end coupled to a casing, with the gearedlever in meshing engagement with a vane gear such that linear movementof the shape memory alloy member rotates the geared lever and the vanegear, which in turn moves the plurality of vanes between the openposition and the closed position, and wherein automatically signalingthe vent assembly to move into the open position includes heating theshape memory alloy member to contract the shape memory alloy member,thereby rotating the geared lever and the vane gear in a first directionto move the plurality of vanes into the open position; closing thehatch; and automatically signaling the vent assembly with the vehiclecontroller to move into the closed position in response to the closingof the hatch; wherein the vent assembly includes a spring operable tourge the plurality of vanes into the closed position, and whereinautomatically signaling the vent assembly to move into the closedposition includes cooling the shape memory alloy member to elongate theshape memory alloy member, thereby allowing the spring to rotate thegeared lever and the vane gear in a second direction to move theplurality of vanes into the closed position.
 12. The method set forth inclaim 11 further comprising not signaling the vent assembly to move intothe open position in response to the opening of the hatch when at leastone of the at least one operating condition of the vehicle is not withinits respective allowable range.
 13. The method set forth in claim 11further comprising sensing if movement of the plurality of vanes betweenthe open position and the closed position is partially blocked by ablockage.
 14. The method set forth in claim 13 further comprising movingthe plurality of vanes into a partially open position, disposed betweenthe closed position and the open position, when the plurality of vanesare blocked from fully moving into the open position by the blockage.15. The method set forth in claim 14 wherein moving the plurality ofvanes into the partially open position is further defined as moving theplurality of vanes toward the open position until the plurality of vanesencounter the blockage preventing further movement of the plurality ofvanes into the open position.